Stabilization of synthetic organic polymeric substances with oxalobis



United States Patent 3 357 944 STABILIZATION Oi S'iZNTHETIC ORGANIC POLYMERIC SUBSTANCES WITH OXALO- 3,357,944 Patented Dec. 12, 1967 in which each of n and m is an integer from 0 to 20. Thus included are compounds of the following three formulae:

Brs sALrcvLInENE HYDRAZIDES) 5 H O O H Martin Dexter, Briarclifi Manor, N.Y., assignor to I ll H Geigy Chemical Corporation, Greenburgh, N.Y., a corporation of Delaware No Drawing. Filed Nov. 26, 1963, Ser. No. 326,242 III 6 Claims. c1. zen-45.9

. 10 OH HO This invention relates to the stabilization of materials alkyl I i I alkyl against deterioration and, more particularly, to methods CH=NNC- N-N=CH@ for preventing, reducing and/ or retarding oxidative deterioration of synthetic organic polymeric substances as W well as the stabilized compositions thus achieved. OH HO By the term synthetic organic polymeric substances is alkyl I H o 0 H I al y intended such solid materials as vinyl resins, as are formed by the polymerization of vinyl halides or by the copolymerization of vinyl halides with other unsaturated 31km alkyl and polymerizable compounds such as vinyl esters, a,,B- V unsaturated acids, a,/3-unsaturated esters, a,,6-unsa-turated ketones, a,B-unsaturated aldehydes and unsaturated hy- By the term, alkyl. as used herem 1s p i i a drocarbons such as butadienes and styrene; poly-a-olefins branched or Stralght chamed hydrocarbon c0n.tammg such as polyethylene, polypropylene, polybutylene and the one to twenty f l Representatlve of like, polyurethanes such as prepared from various polyols groups Wlthout being hmlted thereby are thus met y and organic polyisocyanates; polyamides such as polyethyl propyl i hexyl i decyl hexamethylene adiparnide, polyesters such as polymethyltetradecyltqctadecyl elcosyl the ene terephthalates; as well as other copolymers such as comp 081mm? piepare.d.accordmg to present Inventhose of acrylonitrile, butadiene and/ or styrene, and the l f m addmol? compounds. of the present like. Such substances are often subject to oxidative dete- 3O mventfon vanous other. i such as i i fillers rioration, particularly when in contact with certain catachelatmg agents plasnclzeirs thermal. f t lytic substances Thus for example, while the physical violet absorbers and the like. In addltion, antioxidat ve and mechanical properties of polypropylene make it substances such as hindered phenols, sulfur containing mirably suited for electrical insulation, it is rendered alky.1.eSters and the like oftfm be q with the substantially unsuitable for this use by the oxidation stabllizers of the present invention with superior results promoting properties of even a small amount of copper bemg Observed in the material being insulated. Thus it is found that the T compounds employed the methods and efiective life of polypropylene is reduced by as much as positions of the present invention are prepared by allowa factor of 100 by the presence of as little as 1 or 2 permg an l' :fldehyde of Formula VI to cent of copper. In a like manner, synthetic organic 40 react wlth Xia1d1hYdYaZ1depolymeric substances are often rendered far more prone R ([311 0 0 to oxidation and/or discoloration by catalytic amounts g H of other deteriorative substances. CH0 1 Accordingly, there is provided by the present invention a method of stabilizing such synthetic organic polymeric R1 substances by incorporating therein a stabilizing amount VI of an oxalo b1s hydrazide of the formula. in which R1 and R2 are as defined above on HQ, This reaction is executed by heating in a solvent such R1 I 1 1 E? 1 1 R1 as xylene, ethylene glycol, methanol, water and the like. (JH= -C N= The desired product separates directly upon cooling or is isolated by removal of the solvent as by distillation. R; R2 The following examples, presented by way of illustra- 1 tion and not limitation, will further serve to typify the nature of the present invention. in which each of R and R is hydrogen, alkyl, chloro, E l 1 phenyl, or, taken together, benzo. xamp 8 Also provided by the present invention are novel com- A mixture of 11.8 g. (0.1 mole) of oxalodihydrazide, positions comprising a synthetic organic polymeric sub- 24.4 g. (0.2 mole) of salicylaldehyde and 600 ml. of stance and from about 0.01 to about 5% by weight of a ethylene glycol is heated at reflux temperature for 15 compound according to Formula I, preferably from 0.01 minutes. At the end of this time, the reaction mixture is to 1%. allowed to cool and the solid which forms is collected Particularly valuable compounds embraced by Formula by filtration, washed with methanol and dried to constant I included compounds of the formula: Weight to yield oxalo-bis-(salicylidenehydrazide).

0H 0 H(CmHzm) l H 0 0 H (cmHi...)-H

CH= -I I( -i JI IN=CH (Cn 2n) n 2n)* Example 2 Twenty grams of 4-octadecylphenol, 70 g. of hexarnine and 300 ml. of glacial acetic acid are heated at steam bath temperature of 5 hours. At the end of this time and without cooling, there are added 150 ml. of cone. hydrochloric acid and 150 ml. of water. The mixture is cooled and extracted with benzene and these organic extracts then are washed with water. After removing the benzene solvent by distillation at atmospheric pressure, the residue is distilled in vacuo to yield 2-hydroxy-5-octadecylbenzaldehyde.

By substituting 74.8 g. of 2-hydroxy-5-octadecylbenzaldehyde for salicylaldehyde in the procedure of Example 1, there is obtained oxalo bis (2-hydroxy-5-octadecylbenzylidenehydrazide) Example 3 In a similar fashion, the following compounds are substituted in molar equivalent amounts for salicylaldehyde in the procedure of Example 1.

Z-hydroxy-S-methylbenzaldehyde Z-hydroxy-S-t-butylbenzaldehyde 2-hydroxy-3 ,6-dimethylbenzaldehyde 2-hydroxy-5-t-amylbenzaldehyde 2-hydroxy-3 ,5 -di-t-butylbenzaldehyde 2-hydroxy-S-phenylbenzaldehyde 2-hydroxy-5-chlorobenzaldehyde 2-hydroxyl-naphthaldehyde There are thus respectively obtained the following compounds:

oxalo-bis- (Z-hydroxy-5-methylbenzylidenehydrazide) ox alo-bis- (Z-hydroxy-S -t-butlybenzylidenehydrazide oxalo-bis-(2-hydroxy-3,6-dimethylbenzylidenehydrazide) oxalo-bis-(Z-hydroxy-5-t-amylbenzylidenehydrazide) oxalo-bis-(2-hydroxy-3,5-di-t-butylbenzylidenehydrazide) oxalo-bis- 2-hydroxy-5-phenylbenzylidenehydrazide) oxalo-bis- (2-hydroxy-5-chlorobenzylidenehydrazide) oxalo-bis- 2-hydroxyl-napthylidenehydrazide) Example 4 Stabilized polypropylene is prepared by premixing 0.5% oxalo-bis-(salicylidenehydrazide) with powdered polypropylene with or without auxiliary stabilizers. The mixture is fluxed on a two roll mill at 180 C. for 2 minutes to thoroughly blend the stabilizer and resin. The mixture is then sheeted off, cooled and pressed into sheets, foamed or extruded in a number of shapes. By fitting the extruder with an appropriate head for example, copper wire suitable for electrical use can be coated with the thus stabilized polypropylene insulation which demonstrates unimpaired dielectric properties and excellent stability.

In a similar manner, other of the stabilizers of the present invention are employed in concentrations of from about 0.01 to about 5% for the stabilization of polypropylene. Likewise by blending such stabilizers in other synthetic organic polymeric substances and subjecting such to the usual processing procedures known to the art, superior stabilization can be realized.

As indicated above, stabilizers of this invention often exert a synergistic effect with other stabilizers, some of which are known and others which are the subjects of copending applications. Typical of these but without limiting the same are the following.

(a) dilauryl thiodipropionate (b) n-octadecyl-3,5-di-t-butyl-4-hydroxyphenylacetate (c) N-octadecyl-3,5-di-t-butyl-4-hydroxyphenylacetarhide (d) 2,4 bis (n -octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-tfiazine (e) di n octadecyl-3,5-di-t-butyl-4-hydroxybenzylphosphonate (f) 2 (4 hydroxy 3,5 di t -butylphenoXy)-4,6-bis- (n-octylthioethylthio)-1,3,5-triazine (g) 2,4 bis (4 hydroxy 3,5 di-t-butylphenoxy)-6- octylthio-1,3,5-triazine (h) 1,1,3-tris (2 methyl 4 hydroxy-S-t-butylphenyl) butane (i) trioctadecylphosphite (j) benzotriazole (k) 1,3,5-trimethyl 2,4,6 tri-(3,5-di-t-butyl-4-hydroxybenzyl)benzene It is apparent from the stabilization observed with combinations of the oxalo-bis-hydrazides of the present invention and the auxiliary stabilizers that the former can often potentiate the action of the latter. Such action is also observed with other auxiliary stabilizers when combined with the oxalo-bis-hydrazides of the present invention.

What is claimed is:

1. A composition of matter comprising a synthetic organic polymeric substance normally subject to oxidative deterioration and a stabilizing amount of a compound 5 of the formula:

OH HO Ra Ra wherein R and R (a) taken separately are hydrogen, alkyl, chloro or phenyl and (b) taken on adjacent carbon atoms together with the ring carbon atoms of the benzene ring to which they are attached, are o-phenylene, thereby forming, with said phenyl ring, a naphthyl ring.

2. A composition of matter comprising a synthetic organic polymeric substance normally subject to oxidative deterioration in the presence of copper and a stabilizing amountof a compound of the formula:

OH HO 3. A composition of matter comprising a synthetic organic polymeric substance normally subject to oxidative deterioration in the presence of copper and a stabilizing amount of a compound of the formula:

OH HO alkyl H O O H alkyl References Cited UNITED STATES PATENTS 3,117,104 l/1964 Bown et al. 260-453 DONALD E. CZAJA, Primary Examiner.

LEON I. BERCOVITZ, Examiner.

H. E. TAYLOR, 1a., Assistant Examiner. 

1. A COMPOSITION OF MATTER COMPRISING A SYNTHETIC ORGANIC POLYMERIC SUBSTANCE NORMALLY SUBJECT TO OXIDATIVE DETERIORATION AND A STABILIZING AMOUNT OF A COMPOUND OF THE FORMULA: 